Machine implements such as vibratory compactors are often used in construction and other industries to compact soil, roadway base, paving material, or other work surfaces. In certain applications, the implement is provided as an accessory that is attached to a mobile machine, such as an excavator. The machine typically has its own hydraulic circuit for operating components provided on the machine. For example, the hydraulic circuit of the machine may be connected to hydraulic actuators for operating tracks or other ground engaging units to move the machine over the surface. Additionally, the hydraulic circuit may be coupled to hydraulic cylinders that operate the boom, stick, or other component of the machine. The hydraulic circuit of the machine may also have auxiliary connections, such as a high pressure supply line and a low pressure return line, for attachment to the implement.
The implement, in turn, includes a hydraulic system for routing hydraulic fluid through the implement, thereby to operate the implement. In a vibratory compactor, for example, the hydraulic system includes a primary line coupled to a motor having an inlet and an outlet fluidly coupled to the supply and return lines, respectively, of the machine. The motor may be connected to a vibration mechanism, such as a rotatable shaft carrying an eccentric weight, so that fluid flow through the primary line rotates the shaft to produce a vibratory force. The hydraulic system may include additional lines, such as a bypass line, pressure relief line, and anti-cavitation line, to perform other functions.
In conventional implements, the primary and additional lines are typically provided in a manifold that is located remotely from the motor. For example, the motor may be mounted on a vibratory plate, while the manifold is mounted on a yoke coupled to the plate. Consequently, additional hoses are required to connect the manifold to the pump. Additionally, in some implements, a primary check valve is provided in the primary line to ensure that hydraulic fluid flows only in the intended direction. This check valve is also typically provided in the remotely located manifold.
A hydrostatic transmission for a riding lawn tractor is disclosed in U.S. Pat. No. 7,739,870 entitled, “Hydrostatic Transmission” (hereinafter the '870 patent). The '870 patent discloses a hydrostatic transmission module 14 that includes a single housing that integrates and houses all of the components of the hydrostatic transmission. Specifically, a cover 74 of the transmission module 14 has an integral fluid flow path that forms a part of the hydraulic circuit. While incorporating some of the hydraulic circuit into the cover 74 may reduce complexity of the hydraulic circuit, it nevertheless requires intricate and complex machining of the housing, thereby raising fabrication costs, and yet provides only an extremely limited amount of space for the integrating hydrostatic transmission components.